1. Field
This patent document relates to a semiconductor device, a semiconductor system, and a method for operating the semiconductor device.
2. Description of the Related Art
A system-on-chip (SoC) is a technology that incorporates various function blocks such as a CPU (central processing unit), a memory, an interface, a digital signal processing circuit and an analog signal processing circuit in one semiconductor integrated circuit. Application examples of SoCs include computer systems, electronic systems, and integrated circuits (IC) fabricated for various electronic devices.
The SoC is being developed with more complicated systems by absorbing various functions associated with processors, multimedia, graphics, interfaces and security. If the SoC technology is developed, the space occupied by chips on a circuit board may be reduced. Therefore the size of a product may be scaled down remarkably and noise generated by collisions in networking among chips that otherwise would be separately mounted may be eliminated. Also, power consumption for signal transmission between separated chips may be avoided and the fabrication cost may be reduced.
Such SoCs are being used in information communication devices and various other electronic devices and, recently, they have been applied to portable devices such as smart phones and tablet PCs. In portable devices that use batteries, power consumption is battery leading factor in determining battery life. Therefore it is important to minimize power consumption while still delivering a chip with the performance that is demanded. Since performance (processing speed) and power consumption have a trade-off relationship in semiconductor circuits, it is important to appropriately retain the balance between performance and power consumption, based on the particular application.
One of technologies that is being researched to satisfy both requirements of performance optimization and minimization of power consumption for an SoC is DVFS (dynamic voltage frequency scaling) technology. The DVFS technology controls the frequency and voltage of a semiconductor circuit. As the clock signal frequency in a semiconductor circuit increases in conjunction with a high voltage power supply, the operation speed of the semiconductor circuit increases and power consumption increases as well. Conversely, as the clock signal frequency decreases and the voltage level and the power supply voltage is lowered, the operation speed of the semiconductor circuit decreases and power consumption decreases as well.